Compo-board.



Wu UUM fuel I any,

"cnmeon menu 1 ing UI U90 1 HUI vuvv UNITED STATES PATENT oEEIoE.

MANUFACTURING COMPANY;

WARE.

COMPO-BOABD.

1,076,261. Specification of Letters Patent. No Drawing.

To all 'whom it may concern Be it known that I, MORGAN K. ARM- STRONG, a citizen of the United States, re-- siding at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in compo-Boards; and Ido hereby declare the following to be a full, clear, and exact description of the invention, such aswill en-. able others skilled in the art to which it appertains to make and use the same.

My invention relates to that class of buildmaterial generally known to the trade as compo-board, the said term being used in a sense broad enough t'oinclude so-called plaster-board, and has for its object to provide a material of this kind which, While of low cost, is highly efiicient for the purposes had in view.

To such ends, the invention consists of the construction hereinafter'described and defined in the claims.

The ingredients used in making the improved board are calcined'gypsum, silicate of soda, borax and saw dust. The proportion of the ingredients may be considerably varied, but I have obtained highly satisfactory results by the use of the materials as follows: calcined gypsum 75 per cent., silicate of soda 2% per cent., borax 2 per cent,

saw dust 20 per cent. The term saw dust is used in a liberal sense to include any and all .finely divided wood particles usually treated as refuse at saw mills, and which are, consequently, of very small cost. The proportions above, give aboard that is espe-' Application filed June 28, 1911. Serial No. 685,782.

cially adapted for use as a plaster board,

and when the board is to-be used for other "MORGAN ARMSTRONG, OF MINNEAPOLIS, MINNESOTA, ASSIGNOB- TO BESTWALL OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- Patcnted Oct. 21, 1913.

r 7 purposes, a smaller per cent. of calcined gypsum and a larger 1' cent. of saw dust will preferably be emp oyed. The above inredlents are. first preferably commingled in dry form and are then mixed with water to form a wet conglomerate mass which is then properly distributed and pressed into form and dried to give the finished product or board.

The laster board, or more generally stated, t e compo-board of the above character may be constructed at small cost and is highly eflicient for the various purposes for which it is intended, being, as already indicated, especially eflicient for use as a plaster-board. The silicate of soda serves as a hinder or glue for the saw dust, and the borax serves.as a retardant for preventing too rapid drying or setting of the conglomerate mass, and also contributes to the production of a board, which, when seasoned,

. will be hard and tenacious, or coherent.

'What I claim is:

1. A board of the kind described made of gypsum, silicate of soda, borax, and saw ustr a '2. A board of the kind described composed of approximately seventy-five per cent. (75%) of gypsum, two and one-half per cent. (2.}%) of 'silicate of soda, two and one-half per cent. (2%) of borax, and twenty per cent. (20%) of saw dust.

In testimony whereof I aflix my signature.

in presence of two witnesses.-

- MORGAN K. ARMSTRONG. Witnesses: v

I HORACE Bnow E.-E.'Comis. 

